I have no doubt that if I wanted to work a strict 9-5 schedule I could easily do that as a developer. There are plenty of big companies which have a punch-in/punch-out system. They also pay less than market.
On the other hand, if I'm making hundreds of thousands of dollars a year then I think it's pretty damn reasonable for me to work longer hours and to be available at random times.
They are being paid to create a certain amount of value, and capture what is generally a small fraction of it.
How does your logic scale? If a dev making $200k per annum has to put in 10 hours a day, does an executive making $600k per annum have to put in 30 hours per day?
Developers are not a subjugated underclass. If you really only want to work 40 hours a week, there are tons of employers who will happily hire you as a developer (at a lower salary).
There's no reason you should be entitled to both a high salary and a short working week.
I fully reject the idea that more hours should be a requirement for good pay.
Further, as a startup founder myself, I don't want my employees working much more than a 40 hour week. I have found* I prefer the work produced by someone with work-life balance, than someone who works all the time.
* subjective sampling of colleagues/coworkers/direct reports/hires.
If you are being paid more than the median American, and have options which would still pay more than the median while working less, then complaining about being overworked is ridiculous. There are simple solutions of just getting a different job.
If you don't want people working more, by all means manage your company that way. The market will decide if its an effective strategy.